Trouble in the Tropics?

The Yucatan Peninsula is where Tropical Storm Harvey  will first encounter land.   And  as it does it will weaken.  It is only a bland tropical system as is.  Any interaction with land will weaken it, but trajectory is a huge issue.  Crossing the Peninsula diagonally is best for everyone but those who see significant swells, a few winds and perhap torrential rains.  I am not saying that it is good news for Southern Texas to Lake Carles, LA.

204351_5day_cone_no_line_and_wind

As the 5PM REPORT Came out,  the diagonal path seems to write a different story from above.  There are two considerations.  The strength and its path.   I think perhaps the question is that the system is still only a rather weak TS and any encounter with land may cause it to weaken even further

Strongly feel that this storm may be downgraded and stay a Tropical Depression.  If it does reach TS again,  then something atypical would happening.  Apart from that, little change is expected, as per me.

 

Tropical Storm Harvey Discussion Number 6
NWS National Hurricane Center Miami FL AL092017
500 PM AST Fri Aug 18 2017

Again, there has been little change in the structure of Harvey,
with the low-level center near the eastern edge of a strong, but
poorly organized, convective area. Earlier reports from an Air
Force Reserve Hurricane Hunter aircraft included winds suggesting
an increased intensity. However, due to uncertainties in how
representative these measurements were, no appreciable change in
the central pressure, and no improvement in the structure, the
initial intensity is held at 35 kt.

The initial motion is 275/18. A strong low- to mid-level ridge
north of the cyclone should keep Harvey on this general motion
for the next 3 days or so, with the system moving from the eastern
to the western Caribbean Sea during this time. After 72 h, a
west-northwestward motion with a decrease in forward speed is
expected when Harvey passes near or over portions of Central
America, the Yucatan Peninsula, and eastern Mexico. The new
forecast track is a little faster then the previous track, but
there were only minor changes in the direction. It should be noted
that there is considerable uncertainty about how far north Harvey
might get over the Bay of Campeche, with several of the large-scale
models not bringing the center back over the water on the latest
runs.

The current shear should persist for about the next 48 h, and
thus the intensity forecast continues the trend of slow
strengthening during this time. However, the GFS and ECMWF again
forecast Harvey to degenerate to an open wave during this time, and
the rest of the intensity guidance has trended toward a weaker
cyclone. This lowers the confidence in intensification. After
48 h, conditions appear more favorable for strengthening, with the
main uncertainty being how much land Harvey will encounter. The
intensity forecast will again call for a peak intensity of 60 kt in
72 h, followed by weakening due to land interaction.

 

FORECAST POSITIONS AND MAX WINDS

INIT 18/2100Z 13.4N 62.9W 35 KT 40 MPH
12H 19/0600Z 13.6N 65.7W 35 KT 40 MPH
24H 19/1800Z 13.9N 69.3W 40 KT 45 MPH
36H 20/0600Z 14.2N 73.0W 40 KT 45 MPH
48H 20/1800Z 14.5N 76.7W 45 KT 50 MPH
72H 21/1800Z 15.5N 83.5W 60 KT 70 MPH
96H 22/1800Z 17.5N 88.5W 50 KT 60 MPH…INLAND
120H 23/1800Z 19.0N 92.0W 30 KT 35 MPH…OVER WATER

 

BULLETIN
Tropical Storm Harvey Advisory Number 6
NWS National Hurricane Center Miami FL AL092017
500 PM AST Fri Aug 18 2017

…HARVEY MOVING THROUGH THE EASTERN CARIBBEAN SEA…

 

SUMMARY OF 500 PM AST…2100 UTC…INFORMATION
———————————————-
LOCATION…13.4N 62.9W
ABOUT 130 MI…210 KM WSW OF ST. LUCIA
ABOUT 405 MI…650 KM SSE OF SAN JUAN PUERTO RICO
MAXIMUM SUSTAINED WINDS…40 MPH…65 KM/H
PRESENT MOVEMENT…W OR 275 DEGREES AT 21 MPH…33 KM/H
MINIMUM CENTRAL PRESSURE…1005 MB…29.68 INCHES

 

WATCHES AND WARNINGS
——————–
There are no coastal watches or warnings in effect.

Interests in the Caribbean Sea and the adjacent land areas of
eastern Central American and northern South America should monitor
the progress of Harvey.

 

DISCUSSION AND 48-HOUR OUTLOOK
——————————
At 500 PM AST (2100 UTC), the center of Tropical Storm Harvey was
located near latitude 13.4 North, longitude 62.9 West. Harvey is
moving toward the west near 21 mph (33 km/h) and this general motion
is expected to continue for the next couple of days. On the
forecast track, the center of Harvey will move through the eastern
Caribbean Sea tonight and through the central Caribbean Sea
Saturday and Saturday night.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Slow strengthening is forecast during the next 48 hours.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
mainly to the north of the center.

The estimated minimum central pressure is 1005 mb (29.68 inches).

 

HAZARDS AFFECTING LAND
———————-
RAINFALL: Locally heavy rains could occur tonight over portions of
the Windward Islands and the offshore islands of northern Venezuela.
Locally heavy rains could also occur over Aruba, Bonaire, and
Curacao on Saturday.

NEXT ADVISORY
————-
Next complete advisory at 1100 PM AST.

$$
Forecaster Beven

 

TROPICAL STORM HARVEY FORECAST/ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092017
2100 UTC FRI AUG 18 2017

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE CARIBBEAN SEA AND THE ADJACENT LAND AREAS OF
EASTERN CENTRAL AMERICAN AND NORTHERN SOUTH AMERICA SHOULD MONITOR
THE PROGRESS OF HARVEY.

TROPICAL STORM CENTER LOCATED NEAR 13.4N 62.9W AT 18/2100Z
POSITION ACCURATE WITHIN 40 NM

PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 18 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT……. 60NE 0SE 0SW 60NW.
12 FT SEAS..150NE 0SE 0SW 60NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT…CENTER LOCATED NEAR 13.4N 62.9W AT 18/2100Z
AT 18/1800Z CENTER WAS LOCATED NEAR 13.3N 62.1W

FORECAST VALID 19/0600Z 13.6N 65.7W
MAX WIND 35 KT…GUSTS 45 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 19/1800Z 13.9N 69.3W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 20/0600Z 14.2N 73.0W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 20/1800Z 14.5N 76.7W
MAX WIND 45 KT…GUSTS 55 KT.
34 KT… 60NE 30SE 30SW 60NW.

FORECAST VALID 21/1800Z 15.5N 83.5W
MAX WIND 60 KT…GUSTS 75 KT.
50 KT… 40NE 20SE 20SW 40NW.
34 KT… 80NE 40SE 40SW 80NW.

EXTENDED OUTLOOK. NOTE…ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5…AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 22/1800Z 17.5N 88.5W…INLAND
MAX WIND 50 KT…GUSTS 60 KT.

OUTLOOK VALID 23/1800Z 19.0N 92.0W…OVER WATER
MAX WIND 30 KT…GUSTS 40 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 13.4N 62.9W

NEXT ADVISORY AT 19/0300Z

GULFIR172302115       This satellite picture depicts an irregular storm center on the IR Loop.  It could better organize and center seems kind of oblique looking.

http://www.goes.noaa.gov/HURRLOOPS/gulfir.html

GULFWV172301915

https://radar.weather.gov/ridge/radar.php?rid=amx&product=N0R&overlay=11101111&loop=no

southeast

activity_loop (3)

This chart shows a lot of instability and a few showers and thunderstorms.   Pretty good indicator of enhanced convective activity.  I am not so certain of the forecast path and even a strong circulation.    Right now it is diffuse.  The next few hours may give a few answers.

Meteorologist Larry Olson (Mike Scott) – DWWX–

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